Question

Calculate the number of moles of Cu in 3.8×10213.8×1021 atoms of Cu.

Express your answer using two significant figures.​

Answer 1

6.3×10⁻³ moles of Cu

Step-by-step explanation:

The relation is, that 1 mol of particles are contained by 6.02×10²³ particles.

This is Avogadro's number that explains that: one mole determines the number of fundamental units that are contained in a constant number but they do not depend on the type of material or the type of particle, and this quantity is 6.02 × 10²³

We can make a rule of three:

6.02×10²³ atoms are contained 1 in mol of Cu

Therefore, 3.8×10²¹ atoms will be contained in (3.8×10²¹ . 1) / NA = 6.3×10⁻³ moles